Vacancy Modulating Co3Sn2S2 Topological Semimetal for Aqueous Zinc‐Ion Batteries

Abstract Weyl semimetals (WSMs) with high electrical conductivity and suitable carrier density near the Fermi level are enticing candidates for aqueous Zn‐ion batteries (AZIBs), meriting from topological surface states (TSSs). We propose a WSM Co 3 Sn 2 S 2 cathode for AZIBs showing a discharge plateau around 1.5 V. By introducing Sn vacancies, extra redox peaks from the Sn 4+ /Sn 2+ transition appear, which leads to more Zn 2+ transfer channels and active sites promoting charge‐storage kinetics and Zn 2+ storage capability. Co 3 Sn 1.8 S 2 achieves a specific energy of 305 Wh kg −1 (0.2 Ag −1 ) and a specific power of 4900 Wkg −1 (5 Ag −1 ). Co 3 Sn 1.8 S 2 and Zn x Co 3 Sn 1.8 S 2 benefit from better conductivity at lower temperatures; the quasi‐solid Co 3 Sn 1.8 S 2 //Zn battery delivers 126 mAh g −1 (0.6 Ag −1 ) at −30 °C and a cycling stability over 3000 cycles (2 Ag −1 ) with 85 % capacity retention at −10 °C.